JP6632642B2 - Sheet conveying device and image forming device - Google Patents

Description

  The present invention relates to control of a motor in a sheet conveying apparatus and an image forming apparatus.

  Conventionally, in an image forming apparatus, after processing of a jam that occurred during conveyance of a sheet is performed, whether or not a sheet remains in a conveyance path is determined based on a detection result of a sheet sensor that detects the presence or absence of a sheet. A configuration for detection is known (Patent Document 1).

JP-A-2006-102814

However, in the configuration of Patent Document 1, since it is necessary set only that the conveying path a sensor for detecting a sheet, the image forming apparatus is enlarged. Also, the provision of the sensor increases the cost.

In view of the above-mentioned problem, an object of the present invention is to detect a sheet with high accuracy by a cheaper configuration .

In order to solve the above-described problems, a sheet conveying device according to the present invention includes:
In a sheet conveying device for conveying a sheet,
A loading unit for the sheet Ru are stacked,
A feeding unit for feeding the sheet over bets stacked on the stacking portion,
A first conveying roller for conveying the fed sheet over up by the feeding unit,
A motor for driving the first transport roller;
Phase determining means for determining the rotational phase of the rotor of the motor,
First control means for controlling a drive current flowing through a winding of the motor so that a deviation between a command phase representing a target phase of the rotor and the rotation phase determined by the phase determination means is reduced;
Wherein after the power of the sheet conveying device is switched from the OFF state to the ON state, and, feeding the power supply of the sheet by the first to the feeding portion of the after switching from the OFF state to the ON state transmission is started as executes the first driving for a first predetermined time driving the front Stories first conveying roller before, to the timing, and a second control means for controlling said first control means,
Determining means for determining the presence or absence of the sheet in the nip portion of the first transport roller based on a value of a parameter corresponding to a load torque applied to the rotor during the first drive;
It is characterized by having.

ADVANTAGE OF THE INVENTION According to this invention, a sheet can be detected with high precision by a cheaper structure .

FIG. 2 is a cross-sectional view illustrating the image forming apparatus according to the first embodiment. FIG. 2 is a block diagram illustrating a control configuration of the image forming apparatus according to the first embodiment. FIG. 3 is a diagram illustrating a relationship between a two-phase motor including an A-phase and a B-phase and a rotating coordinate system represented by d-axis and q-axis. FIG. 2 is a block diagram illustrating a configuration of a motor control device according to the first embodiment. FIG. 4 is a diagram illustrating a configuration in which a conveyance roller is driven according to the first embodiment. FIG. 5 is a diagram illustrating an example of a deviation Δθ2 when a sheet is nipped by a conveyance roller 12 and remains on a conveyance path in a state where the sheet is not nipped by a conveyance roller 13 according to the first embodiment. FIG. 9 is a diagram illustrating an example of a deviation Δθ2 in a case where a sheet remains in the conveyance path in a state where the sheet is nipped by both the conveyance roller 12 and the conveyance roller 13. 6 is a flowchart illustrating a method for detecting a sheet remaining on the conveyance path according to the first embodiment. FIG. 4 is a diagram illustrating an example of a deviation Δθ1 according to the first embodiment. FIG. 8 is a diagram illustrating a configuration in which a conveyance roller is driven according to a second embodiment. 9 is a flowchart illustrating a method for detecting a sheet remaining on a conveyance path according to a second embodiment. It is a figure showing an example of deviation Δθ2 concerning a 3rd embodiment. 9 is a flowchart illustrating a method for detecting a sheet remaining on a conveyance path according to a third embodiment. It is a figure showing an example of deviation Δθ1 concerning a 3rd embodiment. FIG. 3 is a block diagram illustrating a configuration of a motor control device that performs speed feedback control. 13 is a flowchart illustrating a method for detecting a sheet remaining on a conveyance path according to a fourth embodiment. FIG. 9 is a diagram illustrating an example of a current value iq of a motor that drives a conveyance roller.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. However, the shapes and relative arrangements of the components described in this embodiment should be appropriately changed depending on the configuration of the apparatus to which the present invention is applied and various conditions. The present invention is not limited to the following embodiments. In the following description, a case where the motor control device is provided in the image forming apparatus will be described, but the motor control device is not limited to the image forming apparatus. For example, the present invention is also used for a sheet conveying device for conveying a sheet such as a recording medium or a document.

[First Embodiment]
[Image forming apparatus]
FIG. 1 is a cross-sectional view illustrating a configuration of a color electrophotographic copying machine (hereinafter, referred to as an image forming apparatus) 100 having a sheet conveying device used in the present embodiment. Note that the image forming apparatus is not limited to a copying machine, and may be, for example, a facsimile machine, a printing machine, a printer, or the like. The recording method is not limited to the electrophotographic method, and may be, for example, an inkjet method. Further, the type of the image forming apparatus may be either monochrome or color.

  Hereinafter, the configuration and functions of the image forming apparatus 100 will be described with reference to FIG. As shown in FIG. 1, the image forming apparatus 100 includes a document feeding device 201, a reading device 202, and an image printing device 301.

  Documents stacked on the document stacking unit 203 of the document feeding device 201 are fed one by one by a paper feed roller 204 and conveyed along a conveyance guide 206 onto a document glass table 214 of the reading device 202. Further, the document is transported at a constant speed by the transport belt 208 and is discharged by a discharge roller 205 to a discharge tray (not shown). The reflected light from the document image illuminated by the illumination 209 at the reading position of the reading device 202 is guided to the image reading unit 111 by the optical system including the reflection mirrors 210, 211, and 212, and the image is read by the image reading unit 111 for each color (yellow). , Magenta, cyan, and black). The image reading unit 111 includes a lens, a CCD that is a photoelectric conversion element, a CCD driving circuit, and the like. The image signal output from the image reading unit 111 is output to the image printing apparatus 301 after various correction processes are performed by the image processing unit 112 including a hardware device such as an ASIC. As described above, the original is read. That is, the document feeding device 201 and the reading device 202 function as a document reading device.

  Further, there are a first reading mode and a second reading mode as the reading mode of the original. The first reading mode is a mode in which the image of the conveyed document is read by the illumination system 209 and the optical system fixed at a predetermined position. The second reading mode is a mode in which an image of a document placed on the document glass 214 of the reading device 202 is read by the moving illumination system 209 and the moving optical system. Normally, an image of a sheet-shaped document is read in the first reading mode, and an image of a bound document such as a book or a booklet is read in the second reading mode.

  Inside the image printing apparatus 301, a sheet storage tray 9 for storing a recording medium is provided. Note that the recording medium is one on which an image is formed by the image forming apparatus. For example, paper, resin sheet, cloth, OHP sheet, label, and the like are included in the recording medium.

  The recording medium stored in the sheet storage tray 9 is sent out by a pickup roller 10 and is conveyed to registration rollers 14 by conveyance rollers 11, 12, and 13.

  The image signal output from the reading device 202 is input to the optical scanning devices 3Y, 3M, 3C, and 3K including the semiconductor laser and the polygon mirror for each color component. Specifically, the image signal related to yellow output from the reading device 202 is input to the optical scanning device 3Y, and the image signal related to magenta output from the reading device 202 is input to the optical scanning device 3M. The image signal related to cyan output from the reading device 202 is input to the optical scanning device 3C, and the image signal related to black output from the reading device 202 is input to the optical scanning device 3K. In the following description, a configuration in which a yellow image is formed will be described, but the same configuration applies to magenta, cyan, and black.

  The outer peripheral surface of the photosensitive drum 1Y is charged by the charger 2Y. After the outer peripheral surface of the photosensitive drum 1Y is charged, a laser beam corresponding to an image signal input from the reading device 202 to the optical scanning device 3Y passes from the optical scanning device 3Y via an optical system such as a polygon mirror to the photosensitive drum. Irradiation is performed on the outer peripheral surface of 1Y. As a result, an electrostatic latent image is formed on the outer peripheral surface of the photosensitive drum 1Y.

  Subsequently, the electrostatic latent image is developed with the toner of the developing device 4Y, and a toner image is formed on the outer peripheral surface of the photosensitive drum 1Y. The toner image formed on the photosensitive drum 1Y is transferred to the transfer belt 6 by a transfer roller 5Y provided at a position facing the photosensitive drum 1Y.

  The yellow, magenta, cyan, and black toner images transferred to the transfer belt 6 are transferred to a recording medium by a transfer roller pair 15. The registration roller 14 feeds the recording medium to the transfer roller pair 15 in synchronization with the transfer timing.

  As described above, the recording medium to which the toner image has been transferred is sent to the fixing device 18 and is heated and pressed by the fixing device 18 so that the toner image is fixed on the recording medium. Thus, the image is formed on the recording medium by the image forming apparatus 100. The recording medium on which the image has been formed is discharged to a discharge tray 19 by a discharge roller 17.

  The image forming apparatus 100 according to the present embodiment is provided with a door 20 for a user to remove a sheet remaining on the conveyance path. The user can remove the sheet remaining on the conveyance path by opening the door 20. Further, the image forming apparatus 100 according to the present embodiment is provided with a door sensor 21 for detecting whether the door 20 is opened or closed.

  The above is the description of the configuration and functions of the image forming apparatus 100.

  FIG. 2 is a block diagram illustrating an example of a control configuration of the image forming apparatus 100. As shown in FIG. 2, the system controller 151 includes a CPU 151a, a ROM 151b, and a RAM 151c. The system controller 151 includes an image processing unit 112, an operation unit 152, an analog / digital (A / D) converter 153, a high-voltage control unit 155, motor control devices 157, 158, 162, sensors 159, an AC driver 160, The sheet detector 700 and the door sensor 21 are connected. The system controller 151 can transmit and receive data and commands to and from each connected unit.

  The CPU 151a executes various sequences related to a predetermined image forming sequence by reading and executing various programs stored in the ROM 151b.

  The RAM 151c is a storage device. The RAM 151c stores various data such as a set value for the high-voltage control unit 155, a command value for the motor control device 157, and information received from the operation unit 152, for example.

  The system controller 151 transmits, to the image processing unit 112, setting value data of various devices provided inside the image forming apparatus 100, which are necessary for image processing in the image processing unit 112. Further, the system controller 151 receives a signal from the sensors 159 and sets a set value of the high-voltage control unit 155 based on the received signal.

  The high-voltage controller 155 supplies a necessary voltage to the high-voltage unit 156 (charging units 2Y, 2M, 2C, 2K, developing units 4Y, 4M, 4C, 4K, etc.) according to the set values set by the system controller 151. I do.

  The motor control device 157 controls a motor (stepping motor) M2 that drives the transport roller 13 according to a command output from the CPU 151a. Further, the motor control device 158 controls a motor (stepping motor) M1 for driving the transport roller 12 according to a command output from the CPU 151a. Further, the motor control device 162 controls a motor (stepping motor) M0 that drives the transport roller 11 according to a command output from the CPU 151a. Although FIG. 2 shows only the motors M0, M1, and M2 as the motors of the image forming apparatus, actually, the image forming apparatus is provided with four or more motors. Further, a configuration in which one motor control device controls a plurality of motors may be employed. Further, in FIG. 2, only three motor control devices are provided, but actually, four or more motor control devices are provided in the image forming apparatus.

  The A / D converter 153 receives the detection signal detected by the thermistor 154 for detecting the temperature of the fixing heater 161, converts the detection signal from an analog signal to a digital signal, and transmits the signal to the system controller 151. The system controller 151 controls the AC driver 160 based on the digital signal received from the A / D converter 153. The AC driver 160 controls the fixing heater 161 so that the temperature of the fixing heater 161 becomes a temperature necessary for performing the fixing process. The fixing heater 161 is a heater used for the fixing process, and is included in the fixing device 18.

  The system controller 151 operates the operation unit 152 to display an operation screen for the user to set the type of recording medium to be used (hereinafter, referred to as a paper type) on a display unit provided in the operation unit 152. Control. The system controller 151 receives information set by the user from the operation unit 152 and controls an operation sequence of the image forming apparatus 100 based on the information set by the user. Further, the system controller 151 transmits information indicating the state of the image forming apparatus to the operation unit 152. The information indicating the state of the image forming apparatus includes, for example, the number of formed images, the progress of the image forming operation, jamming and double feeding of sheets in the document reading apparatus 201 and the image printing apparatus 301, and remaining in the conveyance path. This is information about a sheet or the like. The operation unit 152 displays information received from the system controller 151 on a display unit.

  As described above, the system controller 151 controls the operation sequence of the image forming apparatus 100. The sheet detector 700 will be described later.

[Motor control device]
Next, the motor control device according to the present embodiment will be described. The motor control device according to the present embodiment controls the motor using vector control. In the following description, the following control is performed based on the rotation phase θ as the electrical angle, the command phase θ_ref, the phase of the current, and the like.For example, the electrical angle is converted to a mechanical angle, and the mechanical angle is converted to the mechanical angle. The following control may be performed based on this.

<Vector control>
First, a method in which the motor control device 157 in this embodiment performs vector control will be described with reference to FIGS. Note that the configuration of the motor control devices 158 and 162 is the same as the configuration of the motor control device 157, and thus the description is omitted. Further, the motor in the following description is not provided with a sensor such as a rotary encoder for detecting the rotational phase of the rotor of the motor, but may be provided with a sensor such as a rotary encoder.

  FIG. 3 shows a stepping motor (hereinafter, referred to as a motor) M2 composed of two phases, A phase (first phase) and B phase (second phase), and a rotating coordinate system represented by d-axis and q-axis. FIG. In FIG. 3, in the stationary coordinate system, an α axis, which is an axis corresponding to the A-phase winding, and a β axis, which is an axis corresponding to the B-phase winding, are defined. In FIG. 3, the d-axis is defined along the direction of the magnetic flux generated by the magnetic poles of the permanent magnet used in the rotor 402, and a direction advanced 90 degrees counterclockwise from the d-axis (perpendicular to the d-axis) Along the direction). The angle formed between the α axis and the d axis is defined as θ, and the rotation phase of the rotor 402 is represented by the angle θ. In the vector control, a rotation coordinate system based on the rotation phase θ of the rotor 402 is used. Specifically, in the vector control, a current vector corresponding to a drive current flowing through the winding is a current component in a rotating coordinate system, and a q-axis component (torque current component) for generating torque in the rotor and a winding are used. And a d-axis component (excitation current component) that affects the strength of the magnetic flux passing through the.

  Vector control is a motor that performs phase feedback control to control the value of the torque current component and the value of the excitation current component so that the deviation between the command phase representing the target phase of the rotor and the actual rotation phase is reduced. This is a control method for controlling. Further, the motor is controlled by performing speed feedback control for controlling the value of the torque current component and the value of the excitation current component so that the deviation between the command speed representing the target speed of the rotor and the actual rotation speed is reduced. There are ways.

  FIG. 4 is a block diagram illustrating an example of a configuration of the motor control device 157 that controls the motor M2. Note that the motor control device 157 includes at least one ASIC, and performs each function described below.

As shown in FIG. 4, the motor control device 157 supplies a drive current to a phase controller 502, a current controller 503, a coordinate inverse transformer 505, a coordinate converter 511, and a motor winding as a circuit for performing vector control. And the like. The coordinate converter 511 expresses a current vector corresponding to the drive current flowing through the A-phase and B-phase windings of the motor 509 on the q-axis and the d-axis from the stationary coordinate system represented by the α-axis and the β-axis. Converts coordinates to a rotating coordinate system. As a result, the drive current flowing through the winding is represented by the current value of the q-axis component (q-axis current) and the current value of the d-axis component (d-axis current), which are current values in the rotating coordinate system. Note that the q-axis current corresponds to a torque current that causes the rotor 402 of the motor M2 to generate torque. The d-axis current corresponds to an exciting current that affects the strength of the magnetic flux passing through the winding of the motor M2. The motor control device 157 can independently control the q-axis current and the d-axis current. As a result, the motor control device 157 can efficiently generate the torque necessary for the rotor 402 to rotate by controlling the q-axis current according to the load torque applied to the rotor 402. That is, in the vector control, the magnitude of the current vector shown in FIG. 3 changes according to the load torque applied to the rotor 402.

  The motor control device 157 determines the rotation phase θ of the rotor 402 of the motor M2 by a method described later, and performs vector control based on the determination result. The CPU 151a generates a command phase θ_ref representing the target phase of the rotor 402 of the motor M2, and outputs the command phase θ_ref to the motor control device 157. Note that the command phase θ_ref is set based on the target speed of the rotor of the motor M2 corresponding to the target speed of the peripheral speed of the transport roller 13.

  The subtracter 101 calculates and outputs a deviation Δθ between the rotation phase θ of the rotor 402 of the motor M2 and the command phase θ_ref output from the phase determiner 513.

  The phase controller 502 acquires the deviation Δθ at a period T (for example, 200 μs). The phase controller 502 controls the q-axis current command value iq_ref and the d-axis based on the proportional control (P), the integral control (I), and the differential control (D) so that the deviation Δθ obtained from the subtractor 101 is reduced. A current command value id_ref is generated and output. Specifically, the phase controller 502 sets the q-axis current command value iq_ref and the d-axis current command value id_ref so that the deviation output from the subtractor 101 based on the P control, the I control, and the D control becomes zero. Is generated and output. The P control is a control method for controlling a value to be controlled based on a value proportional to a deviation between a command value and an estimated value. The I control is a control method for controlling a value to be controlled based on a value proportional to a time integral of a deviation between a command value and an estimated value. The D control is a control method for controlling a value to be controlled based on a value proportional to a time change of a deviation between a command value and an estimated value. Although the phase controller 502 in the present embodiment generates the q-axis current command value iq_ref and the d-axis current command value id_ref based on the PID control, the present invention is not limited to this. For example, the phase controller 502 may generate a q-axis current command value iq_ref and a d-axis current command value id_ref based on PI control. Note that when a permanent magnet is used for the rotor 402, the d-axis current command value id_ref that affects the strength of the magnetic flux passing through the winding is normally set to 0, but is not limited thereto.

  The drive current flowing through the A-phase and B-phase windings of the motor M2 is detected by the current detectors 507 and 508, and then converted from an analog value to a digital value by the A / D converter 510. The cycle in which the current detectors 507 and 508 detect the current is, for example, a cycle (for example, 25 μs) that is equal to or shorter than the cycle T in which the phase controller 502 acquires the deviation Δθ.

The current value of the drive current converted from the analog value to the digital value by the A / D converter 510 is expressed as the current values iα and iβ in the stationary coordinate system using the phase θe of the current vector shown in FIG. expressed. Note that the phase θe of the current vector is defined as an angle formed between the α axis and the current vector. I indicates the magnitude of the current vector.
iα = I * cos θe (1)
iβ = I * sin θe (2)

  These current values iα and iβ are input to a coordinate converter 511 and an induced voltage determiner 512.

The coordinate converter 511 converts the current values iα and iβ in the stationary coordinate system into the current value iq of the q-axis current and the current value id of the d-axis current in the rotating coordinate system by the following equation.
id = cosθ * iα + sinθ * iβ (3)
iq = −sin θ * iα + cos θ * iβ (4)

  The coordinate converter 511 outputs the converted current value iq to the subtractor 102. Further, the coordinate converter 511 outputs the converted current value id to the subtractor 103.

  The subtracter 102 calculates a deviation between the q-axis current command value iq_ref and the current value iq, and outputs the deviation to the current controller 503.

  Further, the subtractor 103 calculates a deviation between the d-axis current command value id_ref and the current value id, and outputs the deviation to the current controller 503.

  The current controller 503 generates the driving voltages Vq and Vd based on the PID control such that the input deviations become smaller. Specifically, the current controller 503 generates the driving voltages Vq and Vd so that the input deviations become 0, respectively, and outputs the generated driving voltages to the coordinate inverse transformer 505. That is, the current controller 503 functions as a generation unit. The current controller 503 according to the present embodiment generates the drive voltages Vq and Vd based on the PID control, but is not limited to this. For example, the current controller 503 may generate the drive voltages Vq and Vd based on PI control.

The coordinate inverse converter 505 inversely converts the driving voltages Vq and Vd in the rotating coordinate system output from the current controller 503 into driving voltages Vα and Vβ in the stationary coordinate system by the following equation.
Vα = cos θ * Vd−sin θ * Vq (5)
Vβ = sin θ * Vd + cos θ * Vq (6)

  The coordinate inverse transformer 505 outputs the inversely transformed Vα and Vβ to the induced voltage determiner 512 and the PWM inverter 506.

  The PWM inverter 506 has a full bridge circuit (H bridge circuit). The full bridge circuit is driven by a PWM signal based on the driving voltages Vα and Vβ input from the coordinate inverter 505. As a result, the PWM inverter 506 generates the drive currents iα and iβ according to the drive voltages Vα and Vβ, and supplies the drive currents iα and iβ to the windings of each phase of the motor M2 to drive the motor M2. . That is, the PWM inverter 506 functions as a supply unit that supplies a current to the winding of each phase of the motor M2. In the present embodiment, the PWM inverter has a full-bridge circuit, but the PWM inverter may be a half-bridge circuit or the like.

Next, a method for determining the rotation phase θ will be described. In determining the rotational phase θ of the rotor 402, the values of the induced voltages Eα and Eβ induced in the A-phase and B-phase windings of the motor M2 by the rotation of the rotor 402 are used. The value of the induced voltage is determined (calculated) by the induced voltage determiner 512. Specifically, the induced voltages Eα and Eβ are input to the induced voltage determiner 512 from the A / D converter 510 and the current values iα and iβ, respectively, and are input from the coordinate inverse converter 505 to the induced voltage determiner 512. From the driving voltages Vα and Vβ, it is determined by the following equation.
Eα = Vα−R * iα−L * diα / dt (7)
Eβ = Vβ−R * iβ−L * diβ / dt (8)

  Here, R is the winding resistance, and L is the winding inductance. The values of the winding resistance R and the winding inductance L are values specific to the motor 509 used, and are stored in advance in the ROM 151 b or a memory (not shown) provided in the motor control device 157.

  The induced voltages Eα and Eβ determined by the induced voltage determiner 512 are output to the phase determiner 513.

The phase determiner 513 determines the rotational phase θ of the rotor 402 of the motor 509 based on the ratio between the induced voltage Eα and the induced voltage Eβ output from the induced voltage determiner 512 according to the following equation.
θ = tan ＾ −1 (−Eβ / Eα) (9)

  Note that, in the present embodiment, the phase determiner 513 determines the rotation phase θ by performing an operation based on Expression (9), but is not limited thereto. For example, the phase determiner 513 performs rotation by referring to a table stored in the ROM 151b or the like and showing a relationship between the induced voltage Eα and the induced voltage Eβ and the rotational phase θ corresponding to the induced voltage Eα and the induced voltage Eβ. The phase θ may be determined.

  The rotation phase θ of the rotator 402 obtained as described above is input to the subtractor 101, the coordinate inverse converter 505, the coordinate converter 511, and the sheet detector 700.

  The motor control device 157 repeatedly performs the above control.

  As described above, the motor control device 157 according to the present embodiment performs the vector control for controlling the current value in the rotating coordinate system so that the deviation between the command phase θ_ref and the rotation phase θ is reduced. By performing the vector control, it is possible to suppress the motor from going out of synchronization, the motor noise increasing due to the excess torque, and the power consumption increasing.

[Method of Detecting Sheets Remaining on Conveyance Path]
FIG. 5 is a diagram illustrating a configuration in which the transport roller according to the present embodiment is driven. FIG. 5 shows a state in which the sheet is nipped by the conveying roller 12 and remains in the conveying path.

  As shown in FIG. 5, the transport roller 11 is driven by a motor M0, and the motor M0 is controlled by a motor control device 162. The transport roller 12 is driven by a motor M1, and the motor M1 is controlled by a motor control device 158. The transport roller 13 is driven by a motor M2, and the motor M2 is controlled by a motor control device 157. The motor control devices 157, 158, and 162 shown in FIG. 5 control a motor to be controlled by vector control.

  Hereinafter, a method of detecting a sheet remaining on the conveyance path due to the stoppage of the operation of the image forming apparatus 100 (a method of detecting the presence or absence of a sheet) according to the present embodiment will be described.

  In the following description, the motor control devices 157, 158, and 162 perform phase feedback control based on the command phase θ_ref output from the CPU 151a, but the command phase θ_ref is generated by the CPU 151a based on the target speed of the motor. You. Actually, the CPU 151a outputs a pulse signal to the motor control device, and the number of pulses corresponds to the command phase, and the frequency of the pulses corresponds to the target speed. Further, the target speed is determined based on a target value of the peripheral speed of the roller.

  As shown in FIG. 5, in the present embodiment, an integer N indicating the order from the transport roller 13 to the transport roller 11 is set. For example, N = 1 indicates the transport roller 13 and N = 3 indicates the transport roller 11.

  In the present embodiment, when the operation of the image forming apparatus 100 is restarted (when the power is turned on), the rollers corresponding to the numbers N and N + 1 are driven, and the deviation Δθ in the motor that drives the rollers corresponding to the number N , The sheet detector 700 detects the presence or absence of the remaining paper. That is, in the present embodiment, the presence or absence of the sheet is determined based on a signal output from the motor control device instead of a sensor such as a photo sensor. Note that the sheet detector 700 outputs a signal indicating the presence or absence of a sheet to the CPU 151a as a detection result every time the deviation Δθ is acquired, for example.

  In the present embodiment, the roller corresponding to the number N is driven at the peripheral speed V1, and the roller corresponding to the number N + 1 is driven at the peripheral speed V2. The peripheral speed V1 is a peripheral speed ΔV faster than the peripheral speed V2. That is, in this embodiment, the roller corresponding to the number N (the downstream roller) is driven in a state in which the peripheral speed is higher by ΔV than the roller corresponding to the number N + 1 (the upstream roller). Note that the peripheral speed of the roller when detecting the presence or absence of the residual paper is a peripheral speed that is lower than the peripheral speed of the roller when conveying the sheet when the image forming operation is performed. Specifically, for example, the peripheral speed of the roller when detecting the presence / absence of the residual paper is set to half the peripheral speed of the roller when conveying the sheet when the image forming operation is performed. .

  FIG. 6 shows the deviation Δθ2 of the motor M2 that drives the transport roller 13 when the transport roller 12 and the transport roller 13 are driven when the power of the image forming apparatus 100 is turned on (that is, when N = 1). It is a figure showing an example. Time t1 is a time when the driving of the transport roller 13 is started. In FIG. 6, when the deviation Δθ is a positive value, it means that the rotational phase θ is later than the command phase θ_ref, and when the deviation Δθ is a negative value, the rotational phase θ is the command phase. It means that it is ahead of θ_ref. However, the relationship between the polarity of the deviation Δθ and the rotation phase θ and the command phase θ_ref is not limited to this. For example, when the rotation phase θ is behind the command phase θ_ref, the deviation Δθ is a negative value, and when the rotation phase θ is ahead of the command phase θ_ref, the deviation Δθ is a positive value. .

  When the sheet is transported by the transport roller 12 in a state where the sheet is nipped by the transport roller 12 and not nipped by the transport roller 13, the leading end of the sheet reaches the nip portion of the transport roller 13 being driven. When the sheet is not nipped by the transport roller 13, a torque Tr required to drive the transport roller 13 is applied to the motor M2 that drives the transport roller 13.

  When the sheet is conveyed by the conveying roller 13, the load torque applied to the motor M2 for driving the conveying roller 13 increases and becomes larger than the torque Tr. When the load torque applied to the motor M2 increases, the absolute value of the deviation Δθ fluctuates due to the fact that the rotation phase θ of the rotor of the motor M2 lags behind the command phase θ_ref. Specifically, for example, as shown in FIG. 6, the absolute value of the deviation Δθ increases.

  The dashed line in FIG. 6 indicates the deviation Δθ2 when the transport roller 12 and the transport roller 13 are driven at the same peripheral speed. 6 shows the deviation Δθ2 when the conveying roller 13 is driven at a higher peripheral speed than the conveying roller 12 in a state where the sheet is nipped between the conveying roller 12 and the conveying roller 13.

  When the sheet is conveyed by both the conveyance roller 12 and the conveyance roller 13, the amount of increase in the load torque applied to the motor M <b> 2 is smaller than when the conveyance roller 13 rotates at the same peripheral speed as the conveyance roller 12. The rotation speed of the roller 13 at a higher peripheral speed than the rotation speed of the transport roller 12 is larger. This is because when the transport roller 13 rotates at a higher peripheral speed than the transport roller 12, the transport roller 13 pulls the sheet nipped by the transport roller 12 downstream. As the load torque applied to the transport roller 13 increases, the absolute value of the deviation Δθ increases. Specifically, as shown in FIG. 6, the variation of the deviation Δθ shown by the solid line is larger than the variation of the deviation Δθ shown by the one-dot chain line. By driving the transport roller 13 at a higher peripheral speed than the transport roller 12, the variation of the deviation Δθ can be increased, and the residual paper can be detected with higher accuracy.

  Further, for example, when the conveyance roller 12 and the conveyance roller 13 are driven when the sheet remains in the conveyance path while being nipped by both the conveyance roller 12 and the conveyance roller 13, the sheet is The sheet is transported by both the transport roller 12. At this time, because the transport roller 13 is driven at a higher peripheral speed than the transport roller 12, the transport roller 13 pulls the sheet nipped by the transport roller 12 downstream. As a result, the load torque applied to the motor M2 becomes larger than the torque Tr, and the fluctuation amount of the deviation Δθ can be made larger. Specifically, the deviation Δθ varies, for example, as shown in FIG. The dashed line indicates the deviation Δθ2 when the transport roller 12 and the transport roller 13 are driven at the same peripheral speed, and the solid line indicates the deviation Δθ2 when the transport roller 13 is driven at a higher peripheral speed than the transport roller 12. Show. By driving the transport roller 13 at a higher peripheral speed than the transport roller 12, residual paper can be detected with higher accuracy.

  As described above, the present embodiment is not limited to the case where the sheet is nipped by the transport roller 12 and remains in the transport path without being nipped by the transport roller 13. This is also applied to the case where the sheet remains in the conveyance path while being nipped by both.

  As shown in FIGS. 6 and 7, in the present embodiment, a threshold value Δθth is set as a threshold value of the deviation Δθ for detecting the presence or absence of a sheet. When the acquired absolute value of the deviation Δθ2 is equal to or larger than the threshold Δθth, the sheet detector 700 outputs a signal indicating that the absolute value of the deviation Δθ2 is equal to or larger than the threshold Δθth. When the absolute value of the deviation Δθ2 is smaller than the threshold value Δθth, the sheet detector 700 outputs a signal indicating that the absolute value of the deviation Δθ2 is smaller than the threshold value Δθth.

  Note that the threshold value Δθth is set to a value larger than the maximum absolute value of the deviation Δθ2 assumed when the transport roller 13 is driven in a state where the sheet is not nipped by the transport roller 13. Note that the maximum value of the absolute value of the deviation Δθ2 assumed when the transport roller 13 is driven in a state where the sheet is not nipped by the transport roller 13 is determined based on a result measured in advance by an experiment or the like. .

  Furthermore, the threshold value Δθth is set to a value smaller than the maximum absolute value of the deviation Δθ2 assumed when the sheet is conveyed (nipped) by the conveying roller 13. Note that the maximum value of the absolute value of the deviation Δθ2 assumed when the sheet is conveyed (nipped) by the conveying roller 13 is determined based on a result measured in advance by an experiment or the like.

  That is, the fact that the absolute value of the deviation Δθ2 is equal to or larger than the threshold value Δθth means that the sheet is nipped at the nip portion of the transport roller 13 (the sheet remains).

  FIG. 8 is a flowchart illustrating a method for detecting a sheet remaining on the conveyance path. Hereinafter, a method for detecting a sheet remaining on the conveyance path will be described with reference to FIG. The processing of this flowchart is executed by the CPU 151a. Note that the process of this flowchart is started, for example, when the power of the image forming apparatus 100 is turned on, that is, in a state where the image forming process has not been started yet.

  When the power of the image forming apparatus 100 is turned on, the CPU 151a sets the number N to “1” in S101.

  Thereafter, in S102, the CPU 151a instructs the motor control device that controls the motor that drives the roller corresponding to the number N to drive the motor to be controlled such that the roller corresponding to the number N rotates at the peripheral speed V1. Output. Further, the CPU 151a outputs an instruction to drive the motor to be controlled such that the roller corresponding to the number N + 1 rotates at the peripheral speed V2 to the motor control device that controls the motor that drives the roller corresponding to the number N + 1. As a result, the roller corresponding to the number N is driven at the peripheral speed V1, and the roller corresponding to the number N + 1 is driven at the peripheral speed V2.

  Next, in S103, when a signal indicating that the absolute value of the deviation Δθ in the motor driving the Nth roller driven in S102 is equal to or larger than the threshold value Δθth is output from the sheet detector 700, in S104, The CPU 151a turns on the residual paper flag of the roller corresponding to the number N. Specifically, the CPU 151a stores, for example, the RAM 151c that the sheet is nipped by the roller corresponding to the number N.

  In S103, when the absolute value of the deviation Δθ of the motor driving the Nth roller driven in S102 is smaller than the threshold value Δθth, the process proceeds to S105.

  In S105, if the predetermined time TN1 has not elapsed since the motor was driven in S102, the process returns to S103 again.

  In S105, if the predetermined time TN1 has elapsed since the motor was driven in S102, in S106, the CPU 151a drives the motors for driving the respective rollers so as to stop driving the Nth and (N + 1) th rollers. Is output to the motor control device that controls the motor. As a result, the driving of the Nth and (N + 1) th rollers is stopped.

  The predetermined time TN1 is the time required for the sheet to be conveyed by the (N + 1) th conveying roller rotating at the peripheral speed V2 from the nip of the (N + 1) th conveying roller to the nip of the Nth conveying roller. Is set to That is, the time TN1 is set according to the distance from the nip of the (N + 1) th transport roller to the nip of the Nth transport roller (that is, according to the number N). As described above, in the present embodiment, when the absolute value of the deviation Δθ is equal to or larger than the threshold value Δθth during a period from the start of driving of the N-th transport roller to the elapse of the time TN1, the residual paper flag is turned on. That is, even if the time TN1 has not elapsed, the driving of the Nth and (N + 1) th transport rollers is stopped. If the absolute value of the deviation Δθ does not exceed the threshold value Δθth even after the elapse of the time TN1, the driving of the Nth and (N + 1) th transport rollers is stopped.

  Next, when the number N is smaller than n in S107, in S108, the CPU 151a sets N = N + 1 and returns the processing to S102. Note that n represents the number of rollers (3 in this embodiment) from the transport roller 13 to the most upstream transport roller to be detected as a sheet presence / absence in the transport direction.

  On the other hand, if the number N is equal to or greater than n in S107, the CPU 151a advances the process to S109.

  In S109, if there is a roller whose remaining paper flag is ON, in S110, the CPU 151a displays on the operation unit 152 that the sheet remains inside the image forming apparatus 100 and the place where the sheet remains. Notify the user by displaying it in the section.

  Thereafter, in S111, when the door sensor 21 detects that the door 20 has been opened, the CPU 151a advances the process to S112.

  Then, in S112, when the door sensor 21 detects that the door 20 is closed, in S113, the CPU 151a resets (OFF) the residual paper flags corresponding to all the transport rollers, and returns the processing to S101. . Specifically, the CPU 151a deletes the information of the remaining paper stored in the RAM 151c.

  Thereafter, the CPU 151a repeats the processing of this flowchart until the remaining paper flags corresponding to all the conveyance rollers to be detected as a sheet presence / absence are turned off.

  As described above, in the present embodiment, when the operation of the image forming apparatus 100 is restarted (when the power is turned on), the rollers corresponding to the numbers N and N + 1 are driven, and the rollers corresponding to the number N are driven. The sheet detector 700 detects the presence or absence of a residual sheet based on the deviation Δθ in the motor to be used. The roller corresponding to the number N is driven at a peripheral speed V1, and the roller corresponding to the number N + 1 is driven at a peripheral speed V2 that is ΔV slower than the peripheral speed V1. In this way, by driving the Nth roller at a higher peripheral speed than the (N + 1) th roller, the amount of change in the load torque when the sheet is conveyed to the Nth roller can be increased, and Paper can be detected with higher accuracy.

  As described above, in the present embodiment, the sheet remaining on the conveyance path is detected based on a signal output from the motor control device instead of a sensor such as a photo sensor. As a result, it is possible to determine whether or not the sheet is nipped by the transport rollers (detect remaining paper) without increasing the size of the apparatus or increasing the cost.

  In this embodiment, when the absolute value of the deviation Δθ is equal to or larger than the threshold value Δθth in S103 of the flowchart shown in FIG. 8, the driving of the Nth and (N + 1) th transport rollers is stopped in S106. Not as long. For example, when the absolute value of the deviation Δθ is equal to or more than the threshold value Δθth, the driving of the Nth transport roller may be stopped and the driving of the (N + 1) th transport roller may be continued.

  Further, in the present embodiment, if the state in which the absolute value of the deviation Δθ is less than the threshold value Δθth continues for the predetermined time TN1, the driving of the Nth and (N + 1) th transport rollers is stopped in S106 of the flowchart shown in FIG. This is not the case. For example, even if the state in which the absolute value of the deviation Δθ is less than the threshold value Δθth continues for a predetermined time TN1, the driving of the Nth and (N + 1) th transport rollers may be continued.

  Further, in the present embodiment, the presence or absence of the remaining paper is detected based on the deviation Δθ of the motor that drives the roller corresponding to the number N. However, the present invention is not limited to this. For example, the presence or absence of the remaining paper may be detected based on the deviation Δθ of the motor that drives the roller corresponding to the number N + 1. When the leading edge of the sheet conveyed by the conveying roller 12 rotating at the peripheral speed V2 reaches the conveying roller 13 rotating at the peripheral speed V1, the load torque applied to the motor M1 for driving the conveying roller 12 decreases. This is because a force in the rotation direction acts on the transport roller 12 due to the sheet being nipped by the transport roller 12 being pulled by the transport roller 13. As a result, the absolute value of the deviation Δθ increases due to the fact that the rotation phase θ of the rotor of the motor M1 advances beyond the command phase θ_ref. Specifically, the deviation Δθ varies, for example, as shown in FIG.

  In this embodiment, regardless of whether the absolute value of the deviation Δθ is equal to or larger than the threshold value Δθth in S103 of the flowchart of FIG. 8, if the number N is smaller than n, N = N + 1 is set in S108. . Specifically, when the transport roller 13 and the transport roller 12 are driven (that is, N = 1), the number N is set so that the transport roller 12 and the transport roller 11 are driven in S108. This is not the case. For example, when the absolute value of the deviation Δθ is equal to or greater than the threshold Δθth in S103, the configuration may be such that N = N + 2.

  Specifically, when the transport roller 13 and the transport roller 12 are driven (that is, N = 1) and the absolute value of the deviation Δθ is equal to or larger than the threshold value Δθth, the transport roller 11 and the pickup roller 10 are driven. The number N may be set to be set. When n is 4 or more, the configuration may be such that N = N + 3.

  Further, in the present embodiment, the roller corresponding to the number N (the roller on the downstream side) is driven in a state in which the peripheral speed is higher by ΔV than the roller corresponding to the number N + 1 (the roller on the upstream side), but this is not a limitation. . For example, the roller corresponding to the number N (the roller on the downstream side) may be driven in a state in which the peripheral speed is slower by ΔV than the roller corresponding to the number N + 1 (the roller on the upstream side).

  In the present embodiment, the peripheral speed difference ΔV is set to a predetermined value irrespective of the type (paper type) of the conveyed sheet, but is not limited to this. For example, the peripheral speed difference ΔV may be set according to the paper type set by the user. The peripheral speed difference ΔV corresponding to thick paper may be smaller than the peripheral speed difference ΔV corresponding to thin paper and the peripheral speed difference ΔV corresponding to plain paper. The peripheral speed difference ΔV corresponding to plain paper may be smaller than the peripheral speed difference ΔV corresponding to thin paper.

[Second embodiment]
A description of the same parts as those of the first embodiment in the configurations of the image forming apparatus and the motor control apparatus will be omitted.

  In the first embodiment, the roller corresponding to the number N is driven at the peripheral speed V1, and the roller corresponding to the number N + 1 is driven at the peripheral speed V2. Then, based on the deviation Δθ of the motor that drives the roller corresponding to the number N, the presence or absence of the remaining paper was detected. In this embodiment, when the operation of the image forming apparatus 100 is restarted (when the power is turned on), the rollers corresponding to the number N are driven one by one. That is, in a state in which the upstream roller of the two adjacent transport rollers is not driven and the downstream roller is driven, based on the deviation Δθ of the motor that drives the downstream transport roller, the sheet detector Reference numeral 700 detects the presence or absence of a sheet. Note that the peripheral speed of the roller when detecting the presence or absence of the residual paper is a peripheral speed that is lower than the peripheral speed of the roller when conveying the sheet when the image forming operation is performed. Specifically, for example, the peripheral speed of the roller when detecting the presence / absence of the residual paper is set to half the peripheral speed of the roller when conveying the sheet when the image forming operation is performed. .

  FIG. 10 is a diagram illustrating a configuration in which the transport roller according to the present embodiment is driven. FIG. 10 illustrates a state in which the sheet is nipped by the transport rollers 12 and 13 and remains on the transport path.

  Hereinafter, a method of detecting a sheet remaining on the conveyance path due to the stop of the operation of the image forming apparatus 100 (a method of detecting the presence or absence of a sheet) in the present embodiment will be described.

  When the transport roller 13 is driven in a state where the sheet is not nipped by either the transport roller 12 or the transport roller 13, a torque Tr required to drive the transport roller 13 is applied to the motor M2.

  If the sheet remains in the conveyance path while being held by both the conveyance roller 12 and the conveyance roller 13 and the conveyance roller 13 is driven without driving the conveyance roller 12, the conveyance roller 13 Pulls the sheet nipped by the transport roller 12 to the downstream side. As a result, a torque Tr and a torque Tp required to pull the sheet to the downstream side are applied to the motor M2. The absolute value of the deviation Δθ increases due to the fact that not only the torque Tr but also the torque Tp is applied to the motor M2. Specifically, for example, as shown by a solid line or a dashed line in FIG. 7, the absolute value of the deviation Δθ varies. The amount of change in the absolute value of the deviation Δθ is determined based on the fact that the transport roller 12 and the transport roller 13 are driven while the sheet is nipped by both the transport roller 12 and the transport roller 13 and remains in the transport path. It is not necessarily the same as the variation of the absolute value of the deviation Δθ at that time.

  In the present embodiment, a threshold value Δθth2 is set as a threshold value of the deviation Δθ for detecting the presence or absence of a sheet. When the acquired absolute value of the deviation Δθ is equal to or greater than the threshold value Δθth2, the sheet detector 700 outputs a signal indicating that the absolute value of the deviation Δθ is equal to or greater than the threshold value Δθth2. When the absolute value of the deviation Δθ is smaller than the threshold value Δθth2, the sheet detector 700 outputs a signal indicating that the absolute value of the deviation Δθ is smaller than the threshold value Δθth2.

  The threshold value Δθth2 is set to, for example, a value larger than the maximum value of the deviation Δθ assumed when the transport roller 13 is driven in a state where the sheet is not nipped by the transport roller 13. Note that the maximum value of the deviation Δθ assumed when the transport roller 13 is driven in a state where the sheet is not nipped by the transport roller 13 is determined based on a result measured in advance by an experiment or the like.

  Further, the threshold value Δθth2 is set to a value smaller than the maximum value of the deviation Δθ assumed when the transport roller 13 is driven in a state where the sheet is nipped by both the transport roller 13 and the transport roller 12. Note that the maximum value of the deviation Δθ assumed when the transport roller 13 is driven in a state where the sheet is nipped by both the transport roller 13 and the transport roller 12 is based on a result measured in advance by an experiment or the like. Is determined.

  That is, the fact that the absolute value of the deviation Δθ is equal to or larger than the threshold Δθth2 means that the sheet is nipped at the nip portion of the transport roller 13 (the sheet remains).

  FIG. 11 is a flowchart illustrating a method for detecting a sheet remaining on the conveyance path. Hereinafter, a method of detecting a sheet remaining on the conveyance path will be described with reference to FIG. The processing of this flowchart is executed by the CPU 151a. Note that the process of this flowchart is started, for example, when the power of the image forming apparatus 100 is turned on, that is, in a state where the image forming process has not been started yet.

  When the power of the image forming apparatus 100 is turned on, the CPU 151a sets the number N to “1” in S201.

  Thereafter, in S202, the CPU 151a outputs an instruction to drive the motor to be controlled to the motor control device that controls the motor that drives the roller corresponding to the number N. As a result, the roller corresponding to the number N is driven.

  Next, in S203, when a signal indicating that the absolute value of the deviation Δθ in the motor driving the Nth roller driven in S202 is equal to or greater than the threshold value Δθth2 is output from the sheet detector 700, in S204, The CPU 151a turns on the residual paper flag of the roller corresponding to the number N. Specifically, the CPU 151a stores, for example, the RAM 151c that the sheet is nipped by the roller corresponding to the number N.

  In S203, if the absolute value of the deviation Δθ of the motor driving the Nth roller driven in S202 is smaller than the threshold value Δθth2, the process proceeds to S205.

  In S205, if the predetermined time TN2 has not elapsed since the motor was driven in S202, the process returns to S203 again.

  In S205, if the predetermined time TN2 has elapsed since the motor was driven in S202, in S206, the CPU 151a controls the motor for driving the Nth roller so as to stop driving the Nth roller. Outputs an instruction to the control device. As a result, the driving of the Nth roller is stopped.

  Note that the predetermined time TN2 is a distance between the nip portion of the N-th transport roller and the nip portion of the N-1th transport roller (that is, the downstream side of the N-th transport roller) by the N-th transport roller. Is set to the time required to be transported. That is, the time TN2 is set according to the distance from the nip portion of the N-th transport roller to the nip portion of the (N-1) -th transport roller (that is, according to the number N). As a result, even when the sheet is nipped by the N-th transport roller and not nipped by the (N + 1) -th transport roller, the leading edge of the sheet transported by the N-th transport roller is stopped at the (N-1) -th position. Reaches the nip portion of the transport roller. When the leading edge of the sheet reaches the nip portion of the (N-1) -th transport roller in the stopped state, the sheet bends between the N-th transport roller and the (N-1) -th transport roller. As a result, an elastic force acts on the sheet. Due to the elastic force, a force in a direction opposite to the rotation direction acts on the Nth transport roller. As a result, the load torque applied to the motor driving the N-th transport roller increases, and the absolute value of the deviation Δθ also increases. With such a configuration, it is also possible to detect the remaining paper based on the deviation Δθ that increases.

  As described above, in the present embodiment, when the absolute value of the deviation Δθ is equal to or larger than the threshold value Δθth during a period from the start of driving of the N-th transport roller to the elapse of the time TN2, the residual paper flag is turned on. That is, even if the time TN2 has not elapsed, the driving of the Nth transport roller is stopped. If the absolute value of the deviation Δθ does not exceed the threshold value Δθth even after the elapse of the time TN2, the driving of the Nth transport roller is stopped.

  Next, if the number N is equal to or smaller than n in S207, the CPU 151a sets N = N + 1 in S208, and returns the processing to S202. Note that n represents the number of rollers (3 in this embodiment) from the transport roller 13 to the most upstream transport roller to be detected as a sheet presence / absence in the transport direction.

  On the other hand, if the number N is larger than n in S207, the CPU 151a advances the process to S209.

  The processing from S209 to S213 is the same as the processing from S109 to S113 in FIG. 8, and a description thereof will be omitted.

  As described above, in the present embodiment, when the operation of the image forming apparatus 100 is restarted (when the power is turned on), the rollers corresponding to the number N are driven one by one. The sheet detector 700 detects the presence or absence of residual paper based on the deviation Δθ in the motor that drives the rollers. That is, in a state in which the upstream roller of the two adjacent transport rollers is not driven and the downstream roller is driven, the presence or absence of a sheet is determined based on the deviation Δθ of the motor that drives the downstream transport roller. Is detected. As a result, the absolute value of the deviation Δθ, which increases due to the Nth roller pulling the sheet nipped by the (N + 1) th roller, can be increased, and the residual paper can be detected with higher accuracy. can do.

  As described above, in the present embodiment, the sheet remaining on the conveyance path is detected based on a signal output from the motor control device instead of a sensor such as a photo sensor. As a result, it is possible to determine whether or not the sheet is nipped by the transport rollers (detect remaining paper) without increasing the size of the apparatus or increasing the cost.

  Further, in the present embodiment, regardless of whether the absolute value of the deviation Δθ is equal to or larger than the threshold value Δθth2 in S203 of the flowchart of FIG. 11, if the number N is smaller than n, N = N + 1 is set in S208. . Specifically, when the transport roller 13 is driven (that is, N = 1), the number N is set so that the transport roller 12 is driven in S208, but this is not a limitation. For example, when the absolute value of the deviation Δθ is equal to or more than the threshold value Δθth2 in S203, the configuration may be such that N = N + 2. Specifically, when the transport roller 13 is driven (that is, N = 1) and the absolute value of the deviation Δθ is equal to or larger than the threshold value Δθth2, the number N is set so that the transport roller 11 is driven. May be done. When n is 4 or more, the configuration may be such that N = N + 3.

In the vector control in the first embodiment and the second embodiment, the motor is controlled by performing the phase feedback control. However, the present invention is not limited to this. For example, the motor may be controlled by feeding back the rotation speed ω of the rotor 402. Specifically, as shown in FIG. 15, a speed determiner 514 is provided inside the motor control device, and the speed determiner 514 performs rotation based on the amount of change in the rotation phase θ output from the phase determiner 513 during a predetermined period. Determine the speed ω. The following equation (10) is used to determine the speed.
ω = dθ / dt (10)

  Then, the CPU 151a outputs a command speed ω_ref representing the target speed of the rotor. Further, a speed controller 500 is provided inside the motor control device, and the speed controller 500 generates a q-axis current command value iq_ref and a d-axis current command value id_ref such that a deviation between the rotation speed ω and the command speed ω_ref becomes small. And output. The motor may be controlled by performing such speed feedback control. In the case of such a configuration, the detection of the remaining paper is performed by the method described in the present embodiment, for example, based on the deviation Δω between the rotation speed ω and the command speed ω_ref. The command speed ω_ref is a target speed of the rotor of the motor corresponding to the target speed of the peripheral speed of the roller.

[Third embodiment]
A description of the same parts as those of the first embodiment in the configurations of the image forming apparatus and the motor control apparatus will be omitted.

  In the present embodiment, the roller corresponding to the number N is driven while maintaining the rotation phase of the roller corresponding to the number N + 1, and the presence or absence of the remaining paper is determined based on the deviation Δθ of the motor that drives the roller corresponding to the number N. Is detected. Note that the peripheral speed of the roller when detecting the presence or absence of the residual paper is a peripheral speed that is lower than the peripheral speed of the roller when conveying the sheet when the image forming operation is performed. Specifically, for example, the peripheral speed of the roller when detecting the presence / absence of the residual paper is set to half the peripheral speed of the roller when conveying the sheet when the image forming operation is performed. .

  For example, when N = 1, the transport roller 13 is driven while the rotation phase of the transport roller 12 is maintained, and the presence or absence of a residual sheet is detected based on the deviation Δθ2 output from the motor control device 157. The rotation phase of the transport roller 12 is maintained, for example, when the CPU 151a outputs θ_ref1 set to the predetermined rotation phase θ0 to the motor control device 158. As a result, the motor control device 158 controls the drive current flowing through the winding of the motor M1 such that the rotation phase θ of the rotor of the motor M1 becomes θ0.

  FIG. 12 is a diagram illustrating an example of the deviation Δθ2 of the motor M2 that drives the transport roller 13 in the present embodiment. The solid line in FIG. 12 indicates the deviation Δθ2 when the rotation phase of the conveyance roller 12 is held and the conveyance roller 13 is driven in a state where the sheet is nipped by the conveyance roller 12 and the conveyance roller 13. 12 indicates a case where the transport roller 13 is driven and the transport roller 12 is not driven (current is not supplied to the motor) in a state where the sheet is nipped by the transport roller 12 and the transport roller 13. Is shown in FIG.

  As shown in FIG. 12, the deviation Δθ2 when the rotation phase of the conveyance roller 12 is maintained and the conveyance roller 13 is driven is larger than the deviation Δθ2 when the conveyance roller 13 is driven and the conveyance roller 12 is not driven. . This is because a torque in a direction opposite to the torque for rotating the transport roller 13 in the transport direction is applied to the motor M2 via the sheet due to the rotation phase of the transport roller 12 being maintained.

  As described above, in the present embodiment, the roller corresponding to the number N is driven in a state where the rotation phase of the roller corresponding to the number N + 1 is held, and based on the deviation Δθ of the motor that drives the roller corresponding to the number N. The presence or absence of the remaining paper is detected.

  As shown in FIG. 12, in the present embodiment, a threshold value Δθth3 is set as a threshold value of the deviation Δθ for detecting the presence or absence of a sheet. When the obtained deviation Δθ is equal to or larger than the threshold Δθth3, the sheet detector 700 outputs a signal indicating that the absolute value of the deviation Δθ is equal to or larger than the threshold Δθth3. When the absolute value of the deviation Δθ is smaller than the threshold Δθth3, the sheet detector 700 outputs a signal indicating that the absolute value of the deviation Δθ is smaller than the threshold Δθth3.

  The threshold value Δθth3 is set to, for example, a value larger than the threshold value Δθth2 in the second embodiment.

  The threshold value Δθth3 is a deviation Δθ assumed when the transport roller 13 is driven in a state where the sheet is nipped by both the transport roller 13 and the transport roller 12 and the rotation phase of the transport roller 12 is maintained. Set to a value less than the maximum value. The maximum value of the absolute value of the deviation Δθ assumed when the transport roller 13 is driven in a state where the sheet is nipped by both the transport roller 13 and the transport roller 12 and the rotation phase of the transport roller 12 is maintained. The value is determined based on a result measured in advance by an experiment or the like.

  That is, the fact that the absolute value of the deviation Δθ is equal to or greater than the threshold value Δθth3 means that the sheet is nipped at the nip portion of the transport roller 13 (the sheet remains).

  As described above, in the present embodiment, the threshold value Δθth3 is set to a value larger than the threshold value Δθth2 in order to drive the roller corresponding to the number N while maintaining the rotation phase of the roller corresponding to the number N + 1. As a result, it is possible to prevent the noise from being mixed with the deviation Δθ, and the noise exceeding the threshold value and erroneously detecting the remaining paper.

  FIG. 13 is a flowchart illustrating a method for detecting a sheet remaining on the conveyance path. Hereinafter, a method for detecting a sheet remaining on the conveyance path will be described with reference to FIG. The processing of this flowchart is executed by the CPU 151a. Note that the process of this flowchart is started, for example, when the power of the image forming apparatus 100 is turned on, that is, in a state where the image forming process has not been started yet.

  When the power of the image forming apparatus 100 is turned on, in S301, the CPU 151a sets the number N to “1”.

  Thereafter, in S302, the CPU 151a outputs an instruction to drive the motor to be controlled to the motor control device that controls the motor that drives the roller corresponding to the number N. As a result, the roller corresponding to the number N is driven. Further, the CPU 151a outputs an instruction to the motor control device to hold the rotation phase of the roller corresponding to the number N + 1. As a result, the motor control device controls the motor such that the rotation phase of the motor to be controlled becomes the predetermined rotation phase θ0.

  Next, in S303, when a signal indicating that the absolute value of the deviation Δθ in the motor driving the Nth roller driven in S302 is equal to or greater than the threshold value Δθth3 is output from the sheet detector 700, in S304, The CPU 151a turns on the residual paper flag of the roller corresponding to the number N. Specifically, the CPU 151a stores, for example, the RAM 151c that the sheet is nipped by the roller corresponding to the number N.

  In S303, if the absolute value of the deviation Δθ of the motor driving the Nth roller driven in S302 is smaller than the threshold value Δθth3, the process proceeds to S305.

  In S305, if the predetermined time TN3 has not elapsed since the motor was driven in S302, the process returns to S303 again.

  In S305, if the predetermined time TN3 has elapsed since the motor was driven in S302, in S306, the CPU 151a controls the motor that drives the Nth roller so as to stop driving the Nth roller. Outputs an instruction to the control device. As a result, the driving of the Nth roller is stopped. Further, the CPU 151a outputs an instruction to the motor control device to end the holding of the rotation phase of the roller corresponding to the number N + 1. As a result, the holding of the rotation phase of the roller corresponding to the number N + 1 is ended.

  Note that the predetermined time TN3 is the distance from the nip portion of the N-th transport roller to the nip portion of the N-1th transport roller (that is, the downstream side of the N-th transport roller) by the N-th transport roller. Is set to the time required to be transported. That is, the time TN3 is set according to the distance from the nip portion of the N-th transport roller to the nip portion of the (N-1) -th transport roller (that is, according to the number N). As a result, even when the sheet is nipped by the N-th transport roller and not nipped by the (N + 1) -th transport roller, the leading edge of the sheet transported by the N-th transport roller is stopped at the (N-1) -th position. Reaches the nip portion of the transport roller. When the leading edge of the sheet reaches the nip portion of the (N-1) -th transport roller in the stopped state, the sheet bends between the N-th transport roller and the (N-1) -th transport roller. As a result, an elastic force acts on the sheet. Due to the elastic force, a force in a direction opposite to the rotation direction acts on the Nth transport roller. As a result, the load torque applied to the motor driving the N-th transport roller increases, and the absolute value of the deviation Δθ also increases. With such a configuration, it is also possible to detect the remaining paper based on the deviation Δθ that increases.

  As described above, in the present embodiment, when the absolute value of the deviation Δθ is equal to or larger than the threshold value Δθth during the period from the start of driving of the N-th transport roller to the elapse of the time TN3, the residual paper flag is turned on. That is, even if the time TN3 has not elapsed, the driving of the Nth transport roller is stopped. If the absolute value of the deviation Δθ does not exceed the threshold value Δθth even after the elapse of the time TN3, the driving of the Nth transport roller is stopped.

  Next, in S307, if the number N is equal to or less than n, in S308, the CPU 151a sets N = N + 1 and returns the processing to S302. Note that n represents the number of rollers (3 in this embodiment) from the transport roller 13 to the most upstream transport roller to be detected as a sheet presence / absence in the transport direction.

  On the other hand, if the number N is smaller than n in S307, the CPU 151a advances the process to S309.

  The processing from S309 to S313 is the same as the processing from S109 to S113 in FIG. 8, and a description thereof will be omitted.

  As described above, in the present embodiment, the roller corresponding to the number N is driven while the rotation phase of the roller corresponding to the number N + 1 is held, and based on the deviation Δθ of the motor that drives the roller corresponding to the number N. The presence or absence of the remaining paper is detected. As a result, it is possible to detect the remaining paper with higher accuracy.

  As described above, in the present embodiment, the sheet remaining on the conveyance path is detected based on a signal output from the motor control device instead of a sensor such as a photo sensor. As a result, it is possible to determine whether or not the sheet is nipped by the transport rollers (detect remaining paper) without increasing the size of the apparatus or increasing the cost.

  In the present embodiment, the presence or absence of the remaining paper is detected based on the deviation Δθ of the motor that drives the roller corresponding to the number N, but the present invention is not limited to this. For example, the presence or absence of the remaining paper may be detected based on the deviation Δθ of the motor that drives the roller corresponding to the number N + 1. The deviation Δθ1 when the rotation phase of the transport roller 12 is maintained and the transport roller 13 is driven fluctuates as shown in FIG. 14, for example, due to the drive of the transport roller 13. This is because the rotation phase θ of the rotor of the motor M1 that drives the conveyance roller 12 that rotates in the conveyance direction due to the conveyance roller 13 being driven and the sheet being conveyed in the conveyance direction is equal to the command phase θ_ref (the predetermined phase). This is because the rotation phase advances beyond the rotation phase θ0).

  Further, in the present embodiment, regardless of whether the absolute value of the deviation Δθ is equal to or larger than the threshold value Δθth3 in S303 of the flowchart of FIG. 13, if the number N is smaller than n, N = N + 1 is set in S308. . Specifically, when the transport roller 13 is driven and the rotation phase of the transport roller 12 is held (that is, N = 1), the transport roller 12 is driven in S308 and the rotation phase of the transport roller 11 is held. The number N is set as described above, but is not limited to this. For example, when the absolute value of the deviation Δθ is equal to or larger than the threshold value Δθth3 in S303, N may be set to N + 2. Specifically, if the absolute value of the deviation Δθ is equal to or larger than the threshold value Δθth3 in a state where the transport roller 13 is driven and the rotation phase of the transport roller 12 is held (that is, N = 1), the transport roller 11 The number N may be set so that the rotation phase of the pickup roller 10 is driven and held. When n is 4 or more, the configuration may be such that N = N + 3.

  In the vector control according to the present embodiment, the motor is controlled by performing the phase feedback control. However, the present invention is not limited to this. For example, as described with reference to FIG. 15, a configuration may be employed in which the motor is controlled by feeding back the rotation speed ω of the rotor 402. When the speed feedback control is performed, 0 is output to the motor control device as the command phase ω_ref, thereby suppressing the (N + 1) th roller from being driven due to the Nth roller conveying the sheet. can do. As a result, similar to the case where the rotation phase of the (N + 1) th roller is held, the detection of the remaining paper can be performed with high accuracy.

  Further, by turning on the switching element on the ground side of the full-bridge circuit (H-bridge circuit) of the PWM inverter 506, a brake is applied to the rotation of the rotor by an induced voltage generated in the winding due to the rotation of the rotor. You can also. As a result, similar to the case where the rotation phase of the (N + 1) th roller is held, the detection of the remaining paper can be performed with high accuracy.

[Fourth embodiment]
A description of the same parts as those of the first embodiment in the configurations of the image forming apparatus and the motor control apparatus will be omitted.

  In the second embodiment, even when the sheet is nipped by the N-th transport roller and not nipped by the (N + 1) -th transport roller, the N-th transport roller is driven to detect the residual paper. I explained that you can do it. Specifically, the leading edge of the sheet conveyed by the N-th conveyance roller reaches the nip portion of the (N-1) -th conveyance roller in a stopped state, and the sheet is moved to the N-th conveyance roller and the (N-1) -th conveyance roller. An elastic force acts on the sheet due to bending between the sheet and the sheet. Due to the elastic force, a force in a direction opposite to the rotation direction acts on the N-th transport roller, and the load in the motor increases due to the force in the reverse direction, and the absolute value of the deviation Δθ also increases. It has been described that the residual paper can be detected based on the absolute value of the increasing deviation Δθ in this manner.

  On the other hand, in the first embodiment, even when the sheet is nipped by the N-th transport roller and not nipped by the (N + 1) -th transport roller, the N + 1-th and N-th (or N-th and N−1) Second, it has been described that the residual paper can be detected by driving the transport roller. Specifically, when the (N-1) th transport roller and the (N) th transport roller are driven, the leading edge of the sheet transported by the (N) th transport roller reaches the nip portion of the (N-1) th transport roller. . When the leading edge of the sheet reaches the nip portion of the (N-1) th transport roller and the sheet is transported by both the (N-1) th transport roller and the (N) th transport roller, the Nth transport roller is moved. The deviation Δθ of the driven motor fluctuates. It has been described that the residual paper can be detected based on the deviation Δθ that fluctuates in this manner.

  For example, when the thin paper remains in the transport path, the thin paper has a smaller N- than the variation amount of the deviation Δθ caused by bending between the N-th transport roller and the N-1th transport roller. The fluctuation amount of the deviation Δθ caused by being conveyed by both the first conveyance roller and the Nth conveyance roller is larger. That is, when the thin paper remains in the transport path, the residual paper is determined based on the variation of the deviation Δθ caused by the thin paper bending between the Nth transport roller and the (N-1) th transport roller. The accuracy is higher when the thin paper is performed based on the variation amount of the deviation Δθ caused by the thin paper being conveyed by both the (N−1) th conveyance roller and the Nth conveyance roller than when the thin paper is conveyed. Is detected.

  FIG. 16 is a flowchart illustrating a method for detecting a sheet remaining on the conveyance path according to the present embodiment. Hereinafter, a method of detecting a sheet remaining on the conveyance path will be described with reference to FIG. The processing of this flowchart is executed by the CPU 151a. Note that the process of this flowchart is started, for example, when the power of the image forming apparatus 100 is turned on, that is, in a state where the image forming process has not been started yet.

  When the power of the image forming apparatus 100 is turned on, the CPU 151a sets the number N to “1” in S401.

  Thereafter, in S402, the CPU 151a outputs an instruction to drive the motor to be controlled to the motor control device that controls the motor that drives the roller corresponding to the number N. As a result, the roller corresponding to the number N is driven. The driving of the (N-1) th transport roller is stopped.

  Next, in S403, when a signal indicating that the absolute value of the deviation Δθ in the motor driving the Nth roller driven in S402 is equal to or greater than the threshold value Δθth2 is output from the sheet detector 700, in S404, The CPU 151a turns on the residual paper flag of the roller corresponding to the number N.

  Thereafter, in S405, the CPU 151a outputs an instruction to the motor control device that controls the motor that drives the Nth roller so as to stop driving the Nth roller. As a result, the driving of the Nth roller is stopped. Thereafter, the process proceeds to S412.

  In S403, if the absolute value of the deviation Δθ of the motor driving the Nth roller driven in S402 is smaller than the threshold value Δθth2, the process proceeds to S406.

  In S406, if the predetermined time Ts has not elapsed since the motor was driven in S402, the process returns to S403.

  Further, if the predetermined time Ts has elapsed since the motor was driven in S406, in S407, the CPU 151a sends the motor control device that controls the motor driving the (N−1) th transport roller the peripheral roller to the motor control device. An instruction to drive the motor to be controlled so as to rotate at the speed V1 is output. Further, the CPU 151a outputs an instruction to drive the motor to be controlled such that the transport roller rotates at the peripheral speed V2 to the motor control device that controls the motor that drives the Nth transport roller. As a result, the (N-1) th transport roller is driven at the peripheral speed V1, and the Nth transport roller is driven at the peripheral speed V2.

  The predetermined time Ts is set to a time shorter than a predetermined time TN4 described later. Further, the predetermined time Ts may be deviated by driving the Nth transport roller when the sheet remains in the transport path while being nipped by both the Nth transport roller and the (N + 1) th transport roller. The time is set to be longer than the time required for increasing Δθ. As described above, in the present embodiment, when the absolute value of the deviation Δθ becomes equal to or larger than the threshold value Δθth2 during a period from the start of driving of the N-th transport roller to the elapse of the predetermined time Ts, the residual paper flag is turned on. And the drive of the Nth transport roller is stopped even if the predetermined time Ts has not elapsed. If the absolute value of the deviation Δθ does not exceed the threshold value Δθth2 even after the elapse of the time Ts, the (N−1) th transport roller is driven at the peripheral speed V1, and the Nth transport roller is driven at the peripheral speed V2. You.

  Next, in S408, when a signal indicating that the absolute value of the deviation Δθ of the motor driving the Nth roller is equal to or greater than the threshold value Δθth is output from the sheet detector 700, the CPU 151a sets the number N in S409. The residual paper flag of the corresponding roller is turned ON.

  If the absolute value of the deviation Δθ of the motor driving the Nth roller is less than the threshold Δth in S408, the process proceeds to S410.

  In S410, if the predetermined time TN4 has not elapsed since the motor was driven in S407, the process returns to S408 again.

  In S410, if the predetermined time TN4 has elapsed since the motor was driven in S407, in S411, the CPU 151a drives each roller so as to stop driving the (N-1) th and Nth rollers. An instruction is output to a motor control device that controls the motor to be operated. As a result, the driving of the (N-1) th and Nth rollers is stopped.

  Note that the predetermined time TN4 is that the sheet is conveyed by the N-th transport roller rotating at the peripheral speed V2 from the nip portion of the N-th transport roller to the nip portion of the (N-1) -th transport roller. It is set to the time required. That is, the time TN4 is set according to the distance from the nip portion of the N-th transport roller to the nip portion of the (N-1) -th transport roller (that is, according to the number N). As described above, in the present embodiment, when the absolute value of the deviation Δθ is equal to or larger than the threshold value Δθth during a period from the start of driving of the N-th transport roller to the elapse of the time TN4, the residual paper flag is set to the ON state. That is, even if the time TN4 has not elapsed, the driving of the (N-1) th and Nth transport rollers is stopped. If the absolute value of the deviation Δθ does not exceed the threshold value Δθth even after the elapse of the time TN4, the driving of the (N−1) th and Nth transport rollers is stopped.

  Next, in S412, when the number N is less than n, in S413, the CPU 151a sets N = N + 1 and returns the processing to S402.

  On the other hand, if the number N is equal to or greater than n in S412, the CPU 151a advances the process to S414.

  In S414, if there is a roller for which the residual paper flag is ON, in S415, the CPU 151a displays on the operation unit 152 that a sheet remains inside the image forming apparatus 100 and a place where the sheet remains. Notify the user by displaying it in the section.

  Thereafter, in S416, when the door sensor 21 detects that the door 20 has been opened, the CPU 151a advances the process to S417.

  Then, in S417, when the door sensor 21 detects that the door 20 is closed, in S418, the CPU 151a resets (OFF) the residual paper flags corresponding to all the transport rollers, and returns the processing to S401. . Specifically, the CPU 151a deletes the information of the remaining paper stored in the RAM 151c.

  Thereafter, the CPU 151a repeats the processing of this flowchart until the remaining paper flags corresponding to all the conveyance rollers to be detected as a sheet presence / absence are turned off.

  As described above, in the present embodiment, when detecting the remaining paper, first, the N-th transport roller is driven. The driving of the (N + 1) th and (N-1) th transport rollers is stopped. If the absolute value of the deviation Δθ does not become equal to or larger than the threshold value Δθth2 even after a lapse of a predetermined time Ts from the start of driving of the Nth transport roller, the Nth transport roller is driven at the peripheral speed V2, The first transport roller is driven at the peripheral speed V1.

  As described above, in the present embodiment, when the state in which the absolute value of the deviation Δθ is less than the threshold value Δθth2 continues for a predetermined time Ts, that is, when the sheet nips to at least one of the Nth transport roller and the (N + 1) th transport roller If not, both the Nth transport roller and the (N-1) th transport roller are driven. As a result, for example, when the sheet is nipped by the N-th transport roller and is not nipped by the (N + 1) -th transport roller, the leading edge of the sheet transported by the N-th transport roller is shifted by the (N-1) -th transport roller. It is possible to increase the variation of the deviation Δθ in the motor that drives the N-th transport roller when it reaches the nip. As a result, it is possible to detect the remaining paper with higher accuracy.

  As described above, in the present embodiment, the sheet remaining on the conveyance path is detected based on a signal output from the motor control device instead of a sensor such as a photo sensor. As a result, it is possible to determine whether or not the sheet is nipped by the transport rollers (detect remaining paper) without increasing the size of the apparatus or increasing the cost.

In the present embodiment, when the detection of the residual paper is performed, the driving of the (N + 1) th and (N−1) th conveying rollers is stopped, and the Nth conveying roller is driven first. If the absolute value of the deviation Δθ does not become equal to or larger than the threshold value Δθth2 even after a lapse of a predetermined time Ts from the start of driving of the Nth transport roller, the Nth transport roller is driven at the peripheral speed V2, The first transport roller was driven at the peripheral speed V1. That is, in the present embodiment, the configuration in which the method of the second embodiment is first executed and the method of the first embodiment is executed unless the presence of the remaining paper is immediately detected is described. . For example, the method of the first embodiment may be executed if the method of the third embodiment is executed first and the presence of the remaining paper is not immediately detected. Specifically, while the driving of the (N-1) th transport roller is stopped, the rotation phase of the (N + 1) th transport roller is first held, and the Nth transport roller is driven. If the absolute value of the deviation Δθ does not become equal to or larger than the threshold value Δθth2 even after a lapse of a predetermined time Ts from the start of driving of the Nth transport roller, the Nth transport roller is driven at the peripheral speed V2, The first transport roller is driven at the peripheral speed V1 . With such a configuration, a configuration for detecting the remaining paper may be used.

  In the first to fourth embodiments, the detection of the remaining paper is started when the power of the image forming apparatus 100 is turned on, but the present invention is not limited to this. For example, after the jam processing of the image forming apparatus 100 is completed, the detection of the remaining paper may be started when the image forming apparatus 100 returns from the sleep state. In other words, any configuration may be used as long as the detection of the remaining sheet is started during the period from when the sheet conveyance is stopped to when the sheet feeding operation is restarted. Note that the sleep state corresponds to, for example, a power saving mode for suppressing power consumed by the image forming apparatus 100 when the operation of the image forming apparatus 100 is not performed for a predetermined period.

  In the first to fourth embodiments, the transport roller 13 is set as a roller corresponding to N = 1, but the present invention is not limited to this. For example, the discharge roller 17 may be set as a roller corresponding to N = 1. In this case, for example, the roller corresponding to N = 7 is set to the transport roller 11.

  Further, in the first to fourth embodiments, the threshold value of the deviation Δθ is a predetermined value regardless of the paper type, but the threshold value may be set for each paper type.

  In the first to fourth embodiments, the remaining paper flag of the Nth roller is turned on, but the remaining paper flag of the (N + 1) th roller may be turned on.

  Further, the configuration may be such that the CPU 151a has the function of the sheet detector 700.

  In the first to fourth embodiments, when the sequence for detecting the remaining paper is executed, the time for driving the motor is a predetermined time, but is not limited thereto. For example, the drive time may be changed for each roller or motor to be driven.

In the first embodiment , the second embodiment, and the fourth embodiment, one motor is provided for each roller of N = 1 to 3, but two motors are used with one motor. A configuration in which a roller is driven may be used. For example, a configuration in which the motor M1 drives the transport roller 13 and the transport roller 12 may be employed. In such a configuration, for example, the rotation shaft of the motor M1 is connected to each roller via a clutch, and the motor M1 is connected to and separated from the rollers by a clutch, so that the motor M1 has one or more rollers. Two can be driven.

In the first to fourth embodiments, when the absolute value of the deviation is equal to or larger than the threshold, the sheet detector 700 outputs a signal indicating that the absolute value of the deviation is equal to or larger than the threshold. If the value is less than the threshold, a signal indicating that the absolute value of the deviation is less than the threshold is output, but this is not a limitation. For example, the sheet detector 700 may output a signal to the CPU 151a indicating that the sheet has been nipped by the transport roller when the absolute value of the deviation changes from a value smaller than the threshold to a value equal to or larger than the threshold.

  In the first to fourth embodiments, the detection of the remaining paper is performed based on the deviation Δθ, but the present invention is not limited to this. For example, the detection of the remaining paper may be performed based on the current value iq output from the coordinate converter 511. For example, the current value iq of the motor driving the Nth transport roller in the first embodiment is shown in FIG. 17A, and the current value iq of the motor driving the (N + 1) th transport roller is as shown in FIG. ). At time tc, the sheet nipped by the (N + 1) th conveying roller and not nipped by the (N) th conveying roller is conveyed by the (N + 1) th conveying roller, and the leading end of the sheet is moved to the nip portion of the (N) th conveying roller. Indicates the time of arrival. Note that the change in the current value iq shown in FIG. 17 is an example, and the change in the current value iq is not limited to FIG.

  When the detection of the remaining paper is performed based on the current value iq of the Nth motor, the sheet detector 700 detects that the current value iq changes from a value smaller than the threshold iqth to a value larger than the threshold iqth. Output a signal indicating that is nipped by the Nth transport roller. Further, when the detection of the remaining paper is performed based on the current value iq of the (N + 1) th motor, the sheet detector 700 determines that the current value iq changes from a value larger than the threshold iqth to a value smaller than the threshold iqth. , A signal indicating that the sheet is nipped by the N-th transport roller. It should be noted that even if the residual paper is detected based on a change in the q-axis current command value (target value) iq_ref determined based on the deviation between the command phase θ_ref and the rotation phase θ determined by the phase determiner 513. Good. Further, the detection of the remaining paper may be performed based on a change in the amplitude (magnitude) of the current value iα or iβ in the stationary coordinate system.

  The application of the first to fourth embodiments is not limited to motor control by vector control. For example, the first to fourth embodiments are applied to a motor control device having a configuration for feeding back a rotation phase and a rotation speed.

  In the first to fourth embodiments, a stepping motor is used as a motor for driving a load. However, another motor such as a DC motor may be used. The first to fourth embodiments can be applied not only to the case where the motor is a two-phase motor but also to another motor such as a three-phase motor.

  Note that the deviations Δθ, Δω, the current value iq, the current value iq_ref, and the amplitude of the current value iα or iβ in the stationary coordinate system correspond to parameters corresponding to the load torque applied to the rotor of the motor. The change in the parameter corresponding to the load torque occurs when the sheet is conveyed by the adjacent conveyance rollers (for example, the conveyance rollers 13 and 12).

  In the first to fourth embodiments, a permanent magnet is used as a rotor, but the present invention is not limited to this.

Reference Signs List 9 sheet storage tray 10 pickup roller 11, 12, 13 transport roller 100 image forming apparatus 151a CPU
157, 158, 162 Motor controller 502 Phase controller 513 Phase determiner 700 Sheet detector M0, M1, M2 Stepping motor

Claims (27)

In a sheet conveying device for conveying a sheet,
A loading unit for the sheet Ru are stacked,
A feeding unit for feeding the sheet over bets stacked on the stacking portion,
A first conveying roller for conveying the fed sheet over up by the feeding unit,
A motor for driving the first transport roller;
Phase determining means for determining the rotational phase of the rotor of the motor,
First control means for controlling a drive current flowing through a winding of the motor so that a deviation between a command phase representing a target phase of the rotor and the rotation phase determined by the phase determination means is reduced;
Wherein after the power of the sheet conveying device is switched from the OFF state to the ON state, and, feeding the power supply of the sheet by the first to the feeding portion of the after switching from the OFF state to the ON state transmission is started as executes the first driving for a first predetermined time driving the front Stories first conveying roller before, to the timing, and a second control means for controlling said first control means,
Determining means for determining the presence or absence of the sheet in the nip portion of the first transport roller based on a value of a parameter corresponding to a load torque applied to the rotor during the first drive;
A sheet conveying device comprising: In a sheet conveying device for conveying a sheet,
A loading unit on which the sheet is loaded,
A feeding unit that feeds the sheets stacked on the stacking unit,
A first conveyance roller for conveying the sheet fed by the feeding unit,
A motor for driving the first transport roller;
Phase determining means for determining the rotational phase of the rotor of the motor,
First control means for controlling a drive current flowing through a winding of the motor so that a deviation between a command phase representing a target phase of the rotor and the rotation phase determined by the phase determination means is reduced;
After the jam processing in the sheet conveying device is completed, and before the feeding timing at which the feeding of the sheet is started by the feeding unit first after the processing of the jam is completed, Second control means for controlling the first control means so as to execute a first drive for driving one transport roller for a first predetermined time;
Determining means for determining the presence or absence of the sheet in the nip portion of the first transport roller based on a value of a parameter corresponding to a load torque applied to the rotor during the first drive;
A sheet conveying device comprising: 2. The control device according to claim 1, wherein the first control unit controls the drive current based on a value of a torque current component represented in a rotation coordinate system based on the rotation phase determined by the phase determination unit. 3. Or the sheet conveying device according to 2. In a sheet conveying device for conveying a sheet,
A loading unit for the sheet Ru are stacked,
A feeding unit for feeding the sheet over bets stacked on the stacking portion,
A first conveying roller for conveying the fed sheet over up by the feeding unit,
A motor for driving the first transport roller;
Speed determination means for determining the rotation speed of the rotor of the motor,
First control means for controlling a drive current flowing through a winding of the motor so that a deviation between a command speed representing a target speed of the rotor and a rotation speed determined by the speed determination means is reduced;
Wherein after the power of the sheet conveying device is switched from the OFF state to the ON state, and, feeding the power supply of the sheet by the first to the feeding portion of the after switching from the OFF state to the ON state transmission is started as executes the first driving for a first predetermined time driving the front Stories first conveying roller before, to the timing, and a second control means for controlling said first control means,
Determining means for determining the presence or absence of the sheet in the nip portion of the first transport roller based on a value of a parameter corresponding to a load torque applied to the rotor during the first drive;
A sheet conveying device comprising: In a sheet conveying device for conveying a sheet,
A loading unit on which the sheet is loaded,
A feeding unit that feeds the sheets stacked on the stacking unit,
A first conveyance roller for conveying the sheet fed by the feeding unit,
A motor for driving the first transport roller;
Speed determination means for determining the rotation speed of the rotor of the motor,
First control means for controlling a drive current flowing through a winding of the motor so that a deviation between a command speed representing a target speed of the rotor and a rotation speed determined by the speed determination means is reduced;
After the jam processing in the sheet conveying device is completed, and before the feeding timing at which the feeding of the sheet is started by the feeding unit first after the processing of the jam is completed, Second control means for controlling the first control means so as to execute a first drive for driving one transport roller for a first predetermined time;
Determining means for determining the presence or absence of the sheet in the nip portion of the first transport roller based on a value of a parameter corresponding to a load torque applied to the rotor during the first drive;
A sheet conveying device comprising: The sheet conveyance device has a phase determination unit that determines a rotation phase of the rotor,
5. The method according to claim 4, wherein the first control unit controls the drive current based on a value of a torque current component represented in a rotation coordinate system based on a rotation phase determined by the phase determination unit. Or the sheet conveying device according to 5. The parameter corresponding to the load torque, the sheet conveying apparatus according to any one of claims 1 to 6, characterized in that said deviation. The sheet conveying device has a detecting unit that detects a driving current flowing through the winding,
The sheet conveying device according to claim 3, wherein the parameter corresponding to the load torque is a value of a torque current component of the driving current detected by the detection unit. The sheet conveying device includes a second conveying roller adjacent to the first conveying roller,
The second control means drives the first transport roller and the second transport roller in the first drive,
The determining means includes a feature that, based on the value of the parameter corresponding to the load torque that written to the rotor in the first drive, to determine the presence or absence of the sheet in the nip portion of the first conveying roller The sheet conveying device according to any one of claims 1 to 8, wherein The sheet transport device is adjacent to an upstream transport roller of the first transport roller and the second transport roller in a transport direction in which the sheet is transported, and is more transported than the upstream transport roller. A third transport roller provided upstream in the direction,
The second control means, the drive of the conveying roller and the third conveying roller in a stopped state determination before Symbol upstream before and the feed timing after completion of the determination means in the first driving first 2 Execute the second drive for a predetermined time,
The determination means, based on the value of the corresponding parameter in the load torque that written to the rotor of the motor for driving one of the conveying roller and the third conveying roller of the upstream to the second during driving, sheet conveying apparatus according to claim 9, characterized in that the motor for driving the one to determine the presence or absence of Cie over preparative put into the nip of the conveying roller to be driven. The sheet conveying device according to claim 10 , wherein a peripheral speed of the third conveying roller is lower than a peripheral speed of the upstream conveying roller. The peripheral speed of the upstream transport roller in the transport direction in which the sheet is transported between the first transport roller and the second transport roller is the peripheral speed of the transport direction between the first transport roller and the second transport roller. The sheet conveying apparatus according to any one of claims 9 to 11, wherein the peripheral speed of the sheet conveying roller on the downstream side is lower than the peripheral speed. The sheet conveying device,
In the transport direction in which the sheet is conveyed, a fourth conveyance roller adjacent to the third conveying roller and the third conveying roller provided upstream of the first conveying roller and the second conveyance roller,
Has,
The second control means drives the third transport roller and the fourth transport roller in a stopped state for a second predetermined time after the determination of the determination means in the first drive is completed and before the feeding timing. Start the second drive to
Said determination means, based on the value of the parameter corresponding to the load torque that written to the rotor of the motor that drives one of the fourth conveying roller and the third conveying roller in the second drive, the one sheet conveying device according to claim 9 in which the motor for driving is characterized by determining the presence or absence of Cie over preparative put into the nip of the conveying roller to be driven. The peripheral speed of the transport roller on the upstream side in the transport direction between the third transport roller and the fourth transport roller is the transport speed on the downstream side in the transport direction between the third transport roller and the fourth transport roller. The sheet conveying device according to claim 13 , wherein the peripheral speed of the roller is lower than the peripheral speed of the roller. The transport roller downstream of the third transport roller and the fourth transport roller in the transport direction is adjacent to the transport roller upstream of the first transport roller and the second transport roller in the transport direction. sheet conveying device according to claim 13 or 14, characterized in that. The peripheral speed of the transport roller on the downstream side in the transport direction among the third transport roller and the fourth transport roller is the peripheral speed of the transport roller on the upstream side in the transport direction among the first transport roller and the second transport roller. sheet conveying apparatus according to any one of claims 13 to 15, wherein the slower than the circumferential speed. The sheet conveying device includes a second conveying roller that the sheet is provided upstream of the first conveying roller in the conveying direction to be conveyed,
The second control unit executes a second drive for driving the stopped second transport roller for a second predetermined time after the determination of the determination unit in the first drive is completed and before the feeding timing. And
Said determination means, based on the value of the parameter corresponding to the load torque that written to the rotor of the motor for driving the second conveying roller in said second drive, wherein in the nip portion of the second conveying roller sheet The sheet conveyance device according to claim 1, wherein the presence or absence of the sheet is determined . The sheet conveying device,
A second transport roller provided upstream of the first transport roller in a transport direction in which the sheet is transported;
A third transport roller provided adjacent to the first transport roller and provided downstream of the first transport roller in the transport direction;
Has,
The second control means does not drive the third transport roller and drives the first transport roller in the first drive, and the sheet is present in a nip portion of the first transport roller in the first drive. Is determined by the determination unit, the first transport roller is stopped, and a second drive for driving the stopped second transport roller is started,
The determination unit determines whether the sheet is present in the nip portion of the second transport roller based on a value of a parameter corresponding to a load torque applied to a rotor of a motor that drives the second transport roller in the second drive. Judge,
The second control means does not determine that the sheet is present in the nip portion of the first transport roller even if a second predetermined time has elapsed since the drive of the first transport roller was started in the first drive. In this case, the driving of the third transport roller is started,
The determination unit is configured to perform a determination based on a value of a parameter corresponding to the load torque applied to a rotor of a motor that drives the first transport roller while the third transport roller and the first transport roller are being driven. Determining the presence or absence of the sheet in the nip portion of the first transport roller,
The second predetermined time is shorter than a time required for the sheet to be conveyed by the first conveyance roller from a nip portion of the first conveyance roller to a nip portion of the third conveyance roller in a stopped state. 9. The sheet conveying apparatus according to claim 1, wherein the time is a time. 19. The sheet conveying apparatus according to claim 18, wherein a peripheral speed of the third conveying roller is higher than a peripheral speed of the first conveying roller. It said sheet is a sheet conveying apparatus according to any one of claims 1 to 1 9 driving the conveying roller that is determined to be in nip, characterized in that it is stopped. The sheet conveying device,
Storage means for storing information about the transport roller determined to have the sheet,
Notification means for notifying the information stored in the storage means,
The sheet conveying device according to any one of claims 1 to 20 , comprising: Determine the constant by the determining means, from the restored previous SL sheet conveying device from the sleep state, the period until the after the return from the sleep state first the sheet feeding of by the feeding unit is performed sheet conveying apparatus according to any one of claims 1 to 2 1, characterized in that is carried out. In a sheet conveying device for conveying a sheet,
A conveying roller for conveying the sheet,
A motor for driving the transport roller,
Phase determining means for determining the rotational phase of the rotor of the motor,
First control means for controlling a drive current flowing through a winding of the motor so that a deviation between a command phase representing a target phase of the rotor and the rotation phase determined by the phase determination means is reduced;
After the power of the sheet conveying device is switched from the OFF state to the ON state, and, before the transport of the first said sheet after the power supply is switched from the OFF state to the ON state is started, the previous SL conveying roller to perform a first drive for driving a predetermined time, and a second control means for controlling said first control means,
Determining means for determining the presence or absence of the sheet in the nip portion of the transport roller based on a value of a parameter corresponding to a load torque applied to the rotor during the first drive;
A sheet conveying device comprising: In a sheet conveying device for conveying a sheet,
A conveying roller for conveying the sheet,
A motor for driving the transport roller,
Speed determination means for determining the rotation speed of the rotor of the motor,
First control means for controlling a drive current flowing through a winding of the motor so that a deviation between a command speed representing a target speed of the rotor and a rotation speed determined by the speed determination means is reduced;
After the power of the sheet conveying apparatus is switched from the OFF state to the ON state, and, before the transport of the first said sheet after the power supply is switched from the OFF state to the ON state is started, the previous SL conveying roller to perform a first drive for driving a predetermined time, and a second control means for controlling said first control means,
Determining means for determining the presence or absence of the sheet in the nip portion of the transport roller based on a value of a parameter corresponding to a load torque applied to the rotor during the first drive;
A sheet conveying device comprising: In a sheet conveying device for conveying a sheet,
A conveying roller for conveying the sheet,
A motor for driving the transport roller,
Phase determining means for determining the rotational phase of the rotor of the motor,
First control means for controlling a drive current flowing through a winding of the motor so that a deviation between a command phase representing a target phase of the rotor and the rotation phase determined by the phase determination means is reduced;
Wherein after the processing of jam is completed in the sheet conveying device, and, first to drive the transportable a feed roller first predetermined time before, the transport of the first said sheet after processing of the jam is completed is started Second control means for controlling the first control means so as to execute driving;
Determining means for determining the presence or absence of the sheet in the nip portion of the transport roller based on a value of a parameter corresponding to a load torque applied to the rotor during the first drive;
A sheet conveying device comprising: In a sheet conveying device for conveying a sheet,
A conveying roller for conveying the sheet,
A motor for driving the transport roller,
Speed determination means for determining the rotation speed of the rotor of the motor,
First control means for controlling a drive current flowing through a winding of the motor so that a deviation between a command speed representing a target speed of the rotor and a rotation speed determined by the speed determination means is reduced;
Wherein after the processing of jam is completed in the sheet conveying device, and, first to drive the transportable a feed roller first predetermined time before, the transport of the first said sheet after processing of the jam is completed is started Second control means for controlling the first control means so as to execute driving;
Determining means for determining the presence or absence of the sheet in the nip portion of the transport roller based on a value of a parameter corresponding to a load torque applied to the rotor during the first drive;
A sheet conveying device comprising: A sheet conveying device according to any one of claims 1 to 26 ,
Image forming means for forming an image on a sheet conveyed by the sheet conveying device,
An image forming apparatus comprising:

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